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#1
A20 / T2-OLinuXino-LIME2 eMMC boot i...
Last post by aleix - May 03, 2026, 11:53:34 PMHi,
I've been trying to get the latest Bookworm image (A20-OLinuXino-bookworm-minimal-20260323-113959) running on a T2-OLinuXino-LIME2-e8Gs16M-IND Rev.L, installed to eMMC using `olinuxino-sd-to-emmc`. The board boots fine from SD card but fails to boot standalone from eMMC. After some digging via UART I found a few things that might be related and wanted to share them in case anyone has run into the same situation.
1. fdtfile in uboot.env template
`/usr/lib/u-boot-olinuxino/a20-olinuxino/uboot.env` contains:
2. saveenv fails due to metadata_csum
When trying to fix things from the U-Boot prompt, saving the environment fails:
3. fdtoverlays in uEnv.txt
The default `uEnv.txt` contains a list of overlays in `fdtoverlays=` which produce the following at boot:
Current workaround
With both fixes applied to `uEnv.txt` (empty `fdtoverlays` and correct `fdtfile`), the board boots correctly when an SD card with the same image is present. The SD card U-Boot loads `uEnv.txt` from the eMMC and everything works. For now I am using the SD card as a bootloader carrier with the eMMC as root filesystem, which is functional but not ideal.
Any suggestions on how to get the eMMC to boot standalone would be much appreciated. In particular I am wondering whether there is a way to update the eMMC U-Boot to a version that handles `metadata_csum`, or whether the uboot.env template is expected to be board-specific.
Board info from U-Boot:
Thanks
I've been trying to get the latest Bookworm image (A20-OLinuXino-bookworm-minimal-20260323-113959) running on a T2-OLinuXino-LIME2-e8Gs16M-IND Rev.L, installed to eMMC using `olinuxino-sd-to-emmc`. The board boots fine from SD card but fails to boot standalone from eMMC. After some digging via UART I found a few things that might be related and wanted to share them in case anyone has run into the same situation.
1. fdtfile in uboot.env template
`/usr/lib/u-boot-olinuxino/a20-olinuxino/uboot.env` contains:
Code Select
fdtfile=sun7i-a20-olinuxino-micro.dtb
The EEPROM is read correctly at boot (board identified as T2-OLinuXino-LIME2) but the environment template seems to override this with the MICRO dtb, which causes the kernel to fail finding the root filesystem. Adding `fdtfile=sun7i-a20-olinuxino-lime2.dtb` to `/boot/uEnv.txt` works around this.2. saveenv fails due to metadata_csum
When trying to fix things from the U-Boot prompt, saving the environment fails:
Code Select
Saving Environment to EXT4... Unsupported feature metadata_csum found, not writing.
** Unable to write "/uboot.env" from mmc1:1 **
This means any changes made at the U-Boot prompt are lost on reboot, which makes recovery quite difficult.3. fdtoverlays in uEnv.txt
The default `uEnv.txt` contains a list of overlays in `fdtoverlays=` which produce the following at boot:
Code Select
failed on fdt_overlay_apply(): FDT_ERR_NOTFOUND
base fdt does did not have a /__symbols__ node
make sure you've compiled with -@
Could not find a valid device tree
After this the boot script fails and the board falls through to PXE/network boot. Clearing `fdtoverlays=` in `uEnv.txt` resolves this.Current workaround
With both fixes applied to `uEnv.txt` (empty `fdtoverlays` and correct `fdtfile`), the board boots correctly when an SD card with the same image is present. The SD card U-Boot loads `uEnv.txt` from the eMMC and everything works. For now I am using the SD card as a bootloader carrier with the eMMC as root filesystem, which is functional but not ideal.
Any suggestions on how to get the eMMC to boot standalone would be much appreciated. In particular I am wondering whether there is a way to update the eMMC U-Boot to a version that handles `metadata_csum`, or whether the uboot.env template is expected to be board-specific.
Board info from U-Boot:
Code Select
ID: T2-OLinuXino-LIME2-e8Gs16M-IND Rev.L
U-Boot 2021.04+olimex-1-20250305.102147
Thanks
#2
ESP32 / Re: ESP32-POE-ISO-EA-16MB full...
Last post by Ol!mexGoody - May 02, 2026, 08:34:43 PMThanks!
I didn't want to make a box, rather an AV rack mount.
Here is the finished project.
https://www.printables.com/model/1701766-parametric-olimex-esp32-poe-iso-ea-av-rack-mount-1
It'd be great if I could update it with a rev M external antenna board. For bonus points, do you have the external antenna modeled as well?
Yeah, I tried exporting from KiCad, but like I said I kept running into export errors.
Quote from: LubOlimex on April 23, 2026, 01:54:26 PMIt is a good idea to also look at a ready 3D designs, there are many box designs online for ESP32-POE-ISO that can be used as basis. Our boxes also have 3D design files available for download:
https://www.olimex.com/Products/IoT/ESP32/BOX-ESP32-POE-ISO/
I didn't want to make a box, rather an AV rack mount.
Here is the finished project.
https://www.printables.com/model/1701766-parametric-olimex-esp32-poe-iso-ea-av-rack-mount-1
It'd be great if I could update it with a rev M external antenna board. For bonus points, do you have the external antenna modeled as well?
Quote from: LubOlimex on April 23, 2026, 01:54:26 PMNow for the ESP32-POE-ISO I have exported STEP here:
https://ftp.olimex.com/TEMP/ESP32-PoE-ISO-step-export/ESP32-PoE-ISO_Rev_L.step
Notice that I haven't double checked if the dimensions in the export are 100% consistent with each component. We don't need component height during manufacturing so some components can be a bit off. My advice is to also always compare the STEP file with the real board (empirically measure heights).
In future you can export from KiCAD on your won, it is the free software we use to design these boards. Install KiCAD and download the sources from the GitHub page for ESP32-POE-ISO, open the project file in KiCAD, open the PCB layout editor, and click File -> Export and chose one of the formats. Furthermore, there is a built-in 3D viewer in KiCAD, again open the PCB and navigate to View -> 3D Viewer.
Yeah, I tried exporting from KiCad, but like I said I kept running into export errors.
#3
ESP32 / Re: ESP32-POE-ISO-EA-16MB full...
Last post by Ol!mexGoody - May 02, 2026, 08:28:46 PM@faraz, Are you kidding me!? Start your own post!
#4
A64 / Status of CVE-2026-31431
Last post by mossroy - May 01, 2026, 10:37:09 AMAre Olinuxino devices affected by this serious kernel vulnerability?
https://copy.fail/
The kernel module algif_aead is enabled by default on my Olinuxino A64 devices (installed with bullseye official image from Olimex).
For now, I've applied the workaround of disabling algif_aead kernel module.
https://copy.fail/
The kernel module algif_aead is enabled by default on my Olinuxino A64 devices (installed with bullseye official image from Olimex).
For now, I've applied the workaround of disabling algif_aead kernel module.
#5
New Products release / TuxCon 2026 is approaching!
Last post by olimex - April 28, 2026, 02:40:20 PMJoin the open-source community on May 16–17 in Plovdiv for a free conference dedicated to Linux, open hardware, and open-source software.
14 Talks and 2 Workshops: May 16
Soldering Workshop : May 17
Free entry.
Whether you're into embedded, IoT, or FOSS—this is the place to be.
More info: https://tuxcon.mobi
#TuxCon #OpenSource #FOSS #Linux #Plovdiv
14 Talks and 2 Workshops: May 16
Soldering Workshop : May 17
Free entry.
Whether you're into embedded, IoT, or FOSS—this is the place to be.
More info: https://tuxcon.mobi
#TuxCon #OpenSource #FOSS #Linux #Plovdiv
#6
A64 / Re: Microphone noise with USB ...
Last post by LubOlimex - April 28, 2026, 08:43:33 AMThere is some logic behind this happening, what you can easily try is use extension USB cable so that the USB-WIFI adapter is not plugged next to the board and away from the microphone. Using extension cable will help you determine where the distortion comes from empirically.
#7
A64 / Microphone noise with USB WiFi...
Last post by pavelso - April 28, 2026, 01:55:29 AMHi
i have couple of A64 boards. I use them with microphones and usb WiFi adapters (Ralink)
i have following problems. If i connect USB WiFi adapter with external antenna (not the small dongle with built in antenna), i get extensive digital noise on microphone input. I don't get this noise when USB WiFi adapters with built ion antennas, i don't get this problem. I even tried to use short USB extension to move the adapter a bit further from the board, but the noise is still present.
For power i tried bot battery and external 5V adapter.
The microphone is standard electret capsule connected via shielded cable and 3.5mm jack.
Anybody ever encountered similar problem?
i have couple of A64 boards. I use them with microphones and usb WiFi adapters (Ralink)
i have following problems. If i connect USB WiFi adapter with external antenna (not the small dongle with built in antenna), i get extensive digital noise on microphone input. I don't get this noise when USB WiFi adapters with built ion antennas, i don't get this problem. I even tried to use short USB extension to move the adapter a bit further from the board, but the noise is still present.
For power i tried bot battery and external 5V adapter.
The microphone is standard electret capsule connected via shielded cable and 3.5mm jack.
Anybody ever encountered similar problem?
#8
ESP32 / Re: Board "olimex_esp32-c5-dev...
Last post by LubOlimex - April 27, 2026, 10:52:19 AMThank you for the working version. I am sure people would find it helpful.
If it is not much of a trouble can you test what happens if you change:
"f_flash": "80000000L",
with
"f_boot": "40000000L",
instead.
If it is not much of a trouble can you test what happens if you change:
"f_flash": "80000000L",
with
"f_boot": "40000000L",
instead.
#9
A64 / Re: Debian GNU/Linux 13 (Trixi...
Last post by LubOlimex - April 27, 2026, 08:53:29 AM1. If we could do it, we would but as it is we focused solely on Olimage Linux, the main problem is the audio and video support. They contain some blobs that will never be accepted by mainline and when a customer buys a board with HDMI connector and audio jack he expects to see video output and audio output.
2. Yes, latest image should work with all older revisions of the board.
3. We do that in our images. We read the EEPROM. EEPROM is prepared during testing.
4. There is but maintainers are lazy and it is probably incomplete: https://images.olimex.com/changelog.txt
However, all changes can be seen at the GitHub sources for the u-boot, kernel, etc. All are available. Check chapter 5 of the manual "5. Build information and sources" to find the proper links with sources:
https://raw.githubusercontent.com/OLIMEX/OLINUXINO/master/DOCUMENTS/OLIMAGE/Olimage-guide.pdf
2. Yes, latest image should work with all older revisions of the board.
3. We do that in our images. We read the EEPROM. EEPROM is prepared during testing.
4. There is but maintainers are lazy and it is probably incomplete: https://images.olimex.com/changelog.txt
However, all changes can be seen at the GitHub sources for the u-boot, kernel, etc. All are available. Check chapter 5 of the manual "5. Build information and sources" to find the proper links with sources:
https://raw.githubusercontent.com/OLIMEX/OLINUXINO/master/DOCUMENTS/OLIMAGE/Olimage-guide.pdf
#10
ESP32 / Re: ESP32-POE-ISO-EA-16MB full...
Last post by LubOlimex - April 27, 2026, 08:20:05 AMThese are metal boxes and we don't have CAD models from them, they are manufactured by 3d party manufacturer. We have this plastic box for LIME2 and battery which can be used for LIME too:
https://github.com/OLIMEX/OLINUXINO/tree/master/BOXES/LIME2-PLASTIC-BOX
Also there are many free 3D designs for boxes for LIME board if you search online in yeggi or pritables:
https://www.yeggi.com/q/olimex+a20+olinuxino+lime/
https://www.printables.com/model/1149553-limebox-remix-olimex-olinuxino-lime-a10
https://github.com/OLIMEX/OLINUXINO/tree/master/BOXES/LIME2-PLASTIC-BOX
Also there are many free 3D designs for boxes for LIME board if you search online in yeggi or pritables:
https://www.yeggi.com/q/olimex+a20+olinuxino+lime/
https://www.printables.com/model/1149553-limebox-remix-olimex-olinuxino-lime-a10